Orientation of an object (target such another vehicle) is an important state parameter to be estimated in automotive systems. Although methodology to determine orientation is known these suffer from accuracy problems. Throughout the specification reference to orientations should be understood to include alternatively reference to heading. Thus, for a vehicle travelling in a straight line, the heading will be the same as orientation.
Typically, (host) vehicles may be equipped with radar or lidar systems used to classify the environment in the vicinity of the vehicle such as to e.g. detect moving or static objects around the vehicle. Such systems are used to for example, to estimate the motion state or orientation of other vehicles for automotive perception systems and can be used in Active Safety, Driver Assistance and Autonomous Driving applications. Said radar systems including a radar sensor unit adapted to receive signals emitted from said host vehicle and reflected by said target. Generally, the data captured comprise point detections from emitting a radar signal at a single time-point instance and determining from a plurality of point radar detections measurements therefrom captured from said radar sensor unit. These radar detections, can identify a target vehicle e.g. by a cluster of point detections. These point detections are assumed to be generally from the outside of the vehicle and can be regarded as having x and y coordinates in the horizontal plane (i.e. on a 2-dimention plan view/map). Alternatively, the point detections may be considered polar co-ordinates of range and azimuth.
Known techniques can determine the orientation (or heading) of a vehicle e.g. by tracking a vehicle by radar or lidar systems, and are explained hereinafter. However often these techniques have problems with accuracy. Also, issue with tracking algorithms are introduced delay by time filtering.
It is an object of the invention to correct or refine an orientation estimate of a target such as another vehicle using the spatial distribution of detections from an extended radar target. The technique offers an improvement of estimation accuracy in comparison to methods that do not use spatial information of clustered detections are also specified.